Ento Key

Overview Since the turn of this century, compelling evidence has emerged for a novel class of photoreceptors in the mammalian retina. These neurons are ganglion cells that express the photopigment…

Introduction The optic nerves carry the axons of retinal ganglion cells (RGCs), and these axons transmit all the visual information from the inner retina to the brain. The retina and…

The eye is a complex organ responsible for collecting, focusing, and processing light. Modern genetic analysis indicates that there are many different classes of ganglion cells in the retina that…

The vascular system of the eye The vascular system transports oxygen and metabolites in the human body, ensures thermoregulation of the body and its organs, and is responsible for waste…

Introduction “There is no other portion of physiological optics where one finds so many differing and contradictory ideas as concerns the accommodation of the eye, where in the most recent…

Retinal rods and cones are highly specialized neurons that transform light into an electrical signal (see Chapter 18 ) and provide the sensory input for vision. In contrast to most…

Introduction The electroretinogram (ERG) is a useful tool for objective, noninvasive assessment of retinal function both in the clinic and the laboratory. It is a mass electrical potential that represents…

Overview Phototransduction is the series of biochemical events that leads from photon capture by a photoreceptor cell to its hyperpolarization and slowing of neurotransmitter release at the synapse. This overall…

Introduction The outermost, fibrous tunic of the human eye consists of the cornea and the sclera ( Fig. 4.1A,B ). Both are soft connective tissues that provide structural integrity to…

Introduction The cranium protects the brain and provides scaffolding for facial structures. During primate evolution, the orbits were enlarged and reoriented toward the front of the face. This, along with…